Allow batching samples onto the pending motion event.

This enlarges the window of opportunity for batching to
encompass time spent for the window to become ready (while it is
busy processing the last event).

Change-Id: I3fb5a394ab1b85d6591192678168ca6e35dd9d53
diff --git a/services/input/InputDispatcher.cpp b/services/input/InputDispatcher.cpp
index 253d070..810b709 100644
--- a/services/input/InputDispatcher.cpp
+++ b/services/input/InputDispatcher.cpp
@@ -2524,6 +2524,34 @@
                 return; // done!
             }
 
+            // BATCHING ONTO PENDING EVENT CASE
+            //
+            // Try to append a move sample to the currently pending event, if there is one.
+            // We can do this as long as we are still waiting to find the targets for the
+            // event.  Once the targets are locked-in we can only do streaming.
+            if (mPendingEvent
+                    && (!mPendingEvent->dispatchInProgress || !mCurrentInputTargetsValid)
+                    && mPendingEvent->type == EventEntry::TYPE_MOTION) {
+                MotionEntry* motionEntry = static_cast<MotionEntry*>(mPendingEvent);
+                if (motionEntry->deviceId == deviceId && motionEntry->source == source) {
+                    if (motionEntry->action != action
+                            || motionEntry->pointerCount != pointerCount
+                            || motionEntry->isInjected()) {
+                        // Pending event is not compatible for appending new samples.  Stop here.
+                        goto NoBatchingOrStreaming;
+                    }
+
+                    // The pending motion event is a move and is compatible for appending.
+                    // Do the batching magic.
+                    mAllocator.appendMotionSample(motionEntry, eventTime, pointerCoords);
+#if DEBUG_BATCHING
+                    LOGD("Appended motion sample onto batch for the pending motion event.");
+#endif
+                    mLock.unlock();
+                    return; // done!
+                }
+            }
+
             // STREAMING CASE
             //
             // There is no pending motion event (of any kind) for this device in the inbound queue.